Flue Gas Analysis Table

Introduction

See Flue Gas Analysis

Operation

Using a Flue Gas Analyzer or any meter designed to measure oxygen or carbon-monoxide, and taking the flue gas temperature and the temperature of the combustion air, the following Table can be used to determine combustion efficiency when operating on natural gas. The Temperature Column is the NET Difference between Flue Gas and Combustion Air Temperatures.

(Flue Gas Temp -minus- Combustion Air Temp)

Note that each fuel has its own characteristics. Therefore, these numbers are valid ONLY for natural gas.

Read Combustion Efficiency in the Column under the NET Temperature Difference, in the row for the measured O2% or CO2%.

Excess Air %	Excess O2 %	Excess CO2 %	Combustion Efficiency at Net Temperature Difference
Excess Air %	Excess O2 %	Excess CO2 %	170F	220F	270F	330F	380F	430F	480F	530F	580F
0.0	0.0	11.8	86.3	85.3	84.2	83.0	81.9	80.8	79.7	78.6	77.5
4.5	1.0	11.2	86.2	85.1	84.0	82.7	81.6	80.5	79.3	78.2	77.0
9.5	2.0	10.7	86.1	84.9	83.8	82.4	81.2	80.1	78.9	77.7	76.5
15.0	3.0	10.1	85.9	84.7	83.5	82.1	80.9	79.7	78.4	77.2	75.9
21.1	4.0	9.6	85.7	84.5	83.2	81.7	80.5	79.2	77.9	76.6	75.3
28.1	5.0	9.0	85.5	84.2	82.9	81.3	80.0	78.6	77.3	75.9	74.5
35.9	6.0	8.4	85.3	83.9	82.5	80.9	79.5	78.0	76.6	75.2	73.7
44.9	7.0	7.9	85.0	83.5	82.1	80.3	78.8	77.3	75.8	74.3	72.8
55.3	8.0	7.3	84.7	83.1	81.6	79.7	78.1	76.6	74.9	73.3	71.7
67.3	9.0	6.7	84.3	82.7	81.0	79.0	77.3	75.6	73.9	72.2	70.4
81.6	10.0	6.2	83.9	82.1	80.3	78.2	76.4	74.5	72.7	70.8	68.9
98.7	11.0	5.6	83.4	81.5	79.5	77.2	75.2	73.2	71.2	69.2	67.1
119.7	12.0	5.1	82.7	80.6	78.5	75.9	73.8	71.6	69.4	67.2	64.9
145.8	13.0	4.5	82.0	79.6	77.3	74.4	72.0	69.6	67.1	64.7	62.2
179.5	14.0	3.9	81.0	78.3	75.7	72.4	69.7	67.0	64.2	61.5	58.7
224.3	15.0	3.4	79.6	76.6	73.5	69.8	66.7	63.5	60.4	57.2	54.0

More Information

Flue Gas Analysis

Oxygen Control

Combustion Air Control

Air Infiltration

Exhaust Draft Control

Flue Gas Condensers